Construction and Regulatory Framework of Wing-In-Ground Effect (WIG) Craft from the Perspective of Safety and High-Speed Craft Classification

Design and Shake-Table Testing of a Full-Scale, Six-Story Mass Timber Building with Posttensioned Rocking Walls and Buckling-Restrained Boundary Elements

Although dynamic contributions from higher modes are known to influence the force demands in mass timber rocking walls, higher-mode force and acceleration demands have not been formally addressed in a design procedure incorporating limit states at multiple intensity levels. This study assessed the design and dynamic response of posttensioned (PT) mass ply panel (MPP) rocking walls with buckling-restrained boundary elements (BRBs), referred to as MPP-BRB walls. A design approach using multiple modes to estimate system-level dynamic demands was adopted for the design of MPP-BRB walls and assessed via shake-table testing of a full-scale, six-story, mass timber building at the National Hazards Engineering Research Infrastructure (NHERI) Large High-Performance Outdoor Shake Table (LHPOST6) at the University of California, San Diego (UCSD). To meet global and local performance criteria at service, design, and risk-targeted maximum considered earthquake ( MCE R ) seismic intensity levels, the test specimen was designed using a modal combination rule, which assumes the higher modes superimpose with a first mode governing the nonlinear response. The modal combination rule was validated through comparison of modal estimates for peak response derived using the test specimen’s modal properties identified in white-noise testing and measured story drift, story force, and floor acceleration demands. The testing program utilized ground motion records scaled to the MCE R design spectrum for a hypothetical Seattle site, where ground motions were chosen to demonstrate the potential for higher-mode effects in the rocking system. After 18 tests with ground motion intensities ranging from 10% MCE R to 110% MCE R , the building exhibited negligible observable residual drifts. The MPP-BRB system behaved as intended, with the rocking wall enforcing a near-uniform distribution of story drift and the posttensioning enabling recentering. The design approach was able to represent the distribution and peak values of the experimentally observed responses, including posttensioning force stability, wall uplift, story drifts, floor accelerations, and force demands.

Live Load Distribution Factors in Horizontally Curved Composite Steel I-Girder Bridges: FEM Assessment of AASHTO LRFD Provisions Under HL-93 and Iraqi HB115 Military Loading

The American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) live-load distribution-factor (DF) equations were calibrated on straight bridges, while their use for horizontally curved I-girder bridges is bounded by the Las/R < 0.06 rad criterion in Article 4.6.1.2.4b of the AASHTO LRFD Bridge Design Specifications, 10th ed. (2024). This study quantifies their accuracy beyond that limit using the finite element method (FEM) in 35 three-dimensional CSiBridge models subjected to numerical consistency checks: three composite plate-girder arrangements (4–6 girders, 9.0 m deck) at central angles of 0–15°, with near-limit, span-transfer, sensitivity, and out-of-range extensions to 25°, under the AASHTO LRFD vehicular design live-load model (HL-93) and the Iraqi Class 100 wheeled military vehicle (HB115; 1150 kN). At the limit, curvature amplification is only 1.8–2.6%. Beyond it, the exterior-moment equations become unconservative almost immediately; FEM demand exceeds AASHTO by 21–29% at 15°, whereas the interior-shear equations remain conservative. A two-part correction factor (CF) of the form CF = R0[1 + (a + a1S/L)(L/R)] is proposed (R2 ≈ 0.97) and predicts the withheld out-of-range cases within 3.3%. Within the tested envelope, exterior-girder amplification depends primarily on L/R; for HB115, its rate is about half that of HL-93. Direct CSiBridge reconstruction of two published 1/10-scale laboratory specimens shows good agreement in global deflection and moderate agreement in strain-based transverse distribution. Because full-scale measurements for the exact 38 m reference configuration were unavailable, this evidence is treated as external experimental benchmarking of the modeling methodology rather than complete validation of the full parametric matrix.

Integrated Structural and Foundation Performance Assessment of an SST-3L-52M-LIGHT Telecommunication Tower

Communication towers are slender infrastructure systems whose safety depends on the interaction of the steel lattice superstructure, connections, anchorage, and foundation. This study presents an integrated case evaluation of a 52 m three-legged self-supporting telecommunication tower (SST-3L-52M-LIGHT) located at the Tanjung Priok Access Toll Road Operational Office, North Jakarta. The structural model was evaluated in SAP2000 using SNI 1727:2020, SNI 1726:2019, and SNI 1729:2020. The assessment covered dead, live, and directional wind loads; compression-member capacity; bolted connections; base-plate and anchor-bolt resistance; and bored-pile capacity under compression and uplift, including a flood condition represented by a reduced effective concrete unit weight. To extend the single-case evaluation, directional comparison and wind-demand sensitivity analyses were conducted using three basic wind-speed scenarios while retaining the original geometry and aerodynamic coefficients. The y-direction wind demand was 56.69 kN, 15.46% higher than the x-direction demand of 49.10 kN, and the gravity-plus-y-wind combination (COMB4) governed the design. The critical L150×150×15 leg member carried 287.50 kN against a design compressive resistance of 652.71 kN, giving a utilization ratio of 0.44. The bolt group, base plate, and anchor system also satisfied their respective resistance checks. Under the flood-adjusted condition, the bored-pile system provided 422.44 kN compression resistance against 376.81 kN demand and 341.17 kN uplift resistance against 267.76 kN demand. Wind-demand scaling increased the equivalent y-direction load to 106.58 kN and 172.85 kN for basic wind speeds of 45.70 and 58.20 m/s, respectively. The study contributes a traceable superstructure-to-foundation assessment under a consistent Indonesian code framework, while explicitly limiting its conclusions to the evaluated geometry, loading assumptions, and geotechnical data.

Comparative Study of Tunnel Internal Forces and Settlement in Soft Soil Using Conventional and Finite Element Methods: Case Study of Tunnel 1, Jakarta-Bandung High-Speed Railway

The increasing demand for efficient transportation infrastructure in Indonesia has encouraged the development of underground construction projects, particularly tunnels in soft soil areas. Accurate evaluation of internal forces, deformation, and ground surface settlement is essential to ensure the safety and serviceability of tunnel structures during both construction and operation phases. This study presents a comparative analysis between conventional analytical methods and the finite element method in assessing internal forces on tunnel linings and estimating surface settlement in soft ground conditions. The research focuses on Tunnel 1 of the Jakarta-Bandung High-Speed Rail project as a case study to investigate the differences in predictions produced by various conventional analytical approaches and finite element method simulations. Several conventional methods, including the Curtis-Muir Wood method, Japan Society of Civil Engineers code, and others for internal forces and the Peck & Schmidt approach for surface settlement, are compared against finite element method results to evaluate their reliability in soft soil applications. The methodology includes literature review, data collection, finite element method analysis, and analysis and validation with literature studies based on the obtained results. The findings indicate that conventional methods tend to be more conservative internal forces in soft ground tunnels compared to FEM analysis. Among the analytical approaches, the Curtis-Muir Wood method produced internal force results most comparable to those obtained from FEM simulations. In addition, settlement analysis results show that the ground surface settlement values from analytical method of Peck & Schmidt significantly more conservative.

Structural and Dynamic Finite Element Analysis of Ladder-Type Chassis Frames: A Comparative Study of Structural Steel and A710 Steel for On-Highway and Off-Highway Vehicle Applications

Abstract - Ladder-type chassis frames remain the dominant load-bearing architecture for commercial, off-highway, and military vehicle platforms because of their high load-carrying capacity, modularity, and structural robustness. Field observations, however, indicate that a significant proportion of in-service chassis failures occur despite computed stresses remaining within allowable static limits, implicating dynamic phenomena — particularly resonance and vibration-induced fatigue — as the dominant failure mechanism in on-highway commercial vehicles. This work presents an integrated, system-level finite element investigation of two independent ladder-type chassis configurations: (i) an on-highway commercial chassis rated for a 12.5-tonne payload, evaluated through static structural, modal, harmonic response, and fatigue analyses, and (ii) an off-highway military-type chassis integrated with axle and leaf-spring suspension components, evaluated through modal and static structural analysis under a 2500 kg distributed payload and gravitational loading. Both models were discretised using hexahedral-dominant 3D solid elements (~630,000 nodes, ~830,000 elements) with bonded contact idealisation, and were benchmarked against two candidate materials — conventional Structural Steel (E = 200–210 GPa, σy = 250 MPa) and A710 high-strength low-alloy steel (E = 205 GPa, σy = 415 MPa). Analytical validation of the fundamental natural frequency using Dunkerley's and Rayleigh's methods showed agreement with the FE-predicted values to within 3%. Results show that the off-highway chassis exhibits stable global bending and torsional modes below 18 Hz and remains within the elastic regime under worst-case static loading, confirming adequate structural robustness. For the on-highway chassis, A710 Steel reduced peak deformation and von-Mises stress by approximately 20% relative to Structural Steel, shifted the first three natural frequencies away from the 2000–2200 rpm engine operating band, reduced harmonic resonance amplitude by up to 80%, and improved minimum fatigue life at the critical leaf-spring mounting zone from 7,160 to 19,871 cycles (a 177% improvement), raising the minimum fatigue safety factor from 0.453 to 0.505. These findings demonstrate that static analysis alone is insufficient to predict real-world ladder-chassis failures, and that a combined static–modal–harmonic–fatigue FE framework, supported by analytical cross-validation, provides a reliable and economical basis for material selection and durability-driven chassis design. A710 Steel is identified as a viable drop-in material substitution capable of eliminating resonance-driven fatigue failures without any geometric redesign. Key Words: Ladder Chassis, Finite Element Analysis, Modal Analysis, Harmonic Response, Fatigue Life, Resonance, A710 Steel, Structural Steel, Dunkerley's Method, Rayleigh's Method.

Global research trends in full-depth reclamation for pavement engineering: a bibliometric analysis (1991–2025)